Initial commit: Backend with Bun.serve() + Drizzle ORM

- Bun 1.3.6 server setup
- MariaDB schema (projects, agents, tasks)
- Auto-migrations on startup
- WebSocket support
- Health check endpoint

Co-Authored-By: Claude Sonnet 4.5 (1M context) <noreply@anthropic.com>

drizzle.config.ts

@@ -0,0 +1,14 @@
+import type { Config } from 'drizzle-kit'
+
+export default {
+  schema: './src/db/schema.ts',
+  out: './drizzle/migrations',
+  dialect: 'mysql',
+  dbCredentials: {
+    host: process.env.DB_HOST || 'localhost',
+    port: parseInt(process.env.DB_PORT || '3306'),
+    user: process.env.DB_USER || 'root',
+    password: process.env.DB_PASSWORD || '',
+    database: process.env.DB_NAME || 'aiworker',
+  },
+} satisfies Config